constitutive heterochromatin


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constitutive heterochromatin

[′kän·stə‚tüd·iv ¦hed·ə·rō′krō·məd·ən]
(genetics)
A type of heterochromatin that is always condensed and is often centered on either side of the centromere, and that stains to give a C band.
References in periodicals archive ?
The general distribution pattern of the constitutive heterochromatin was similar in the two populations with pericentromeric and/or interstitial blocks in some chromosomes pairs, besides conspicuous terminal blocks coinciding with NORs (Figure 2e, f).
Mutability of constitutive heterochromatin (C-bands) during eukaryotic chromosomal evolution and their cytological meaning.
By using C-banding constitutive heterochromatin regions were observed on the centromeres of several chromosomes in all species.
The distribution of constitutive heterochromatin (C-banding) in this specimen showed pericentromeric bands in all autosomes.
The analysis of the C-banding pattern revealed large blocks of constitutive heterochromatin located on the pericentromeric regions of all chromosomes (Figure 2), and the first pair presented a completely heterochromatic long arm.
Constitutive heterochromatin blocks were located at centromeric and telomeric regions of practically all chromosomes, some being more conspicuous than others.
Giemsa C-banding technique, which stains constitutive heterochromatin, is a powerful technique that can be used to identify individual chromosomes and has been successfully used to establish genomic relationships among several species including Allium, Medicago, Cicer, and Triticeae species (Vosa, 1975; Cai and Chinnappa, 1987; Gill and Sears, 1988; Tayyar et al.
Constitutive heterochromatin, G-bands and Robertsonian rearrangements in the chromosomes of Akodon molinae (Rodentia: Cricetidae).
During the cell cycle and meiosis, autosomal heterochromatin is typically highly condensed, and the DNA is thought to be inaccessible to the enzymes involved in recombination (Stack, 1984); similarly, the compact nature of constitutive heterochromatin may prevent penetration of the enzymes involved in the integration of mys retrotransposons.
The point is that quantitative Q-HRs variability only exists in man, though this type of constitutive heterochromatin is present in the genome of two other higher primates: Pan troglodytes and Goriila goriila [4-6].